The present invention pertains generally to valves, and more particularly to valves employing ball lock seats.
Control valves are used in various applications such as pressure regulators, solenoid valves, etc. The weak link of most systems employing control valves is the control valve itself. The general lack of reliability of control valves, especially solenoid valves, results from problems such as sticking, seat cutting and leaking. To obtain a satisfactory seal, many solenoid valves use rubber or derivatives of rubber or elastomers such as Viton which has sufficient flexibility to provide a seal under most operating conditions. However, such sealing devices are often affected by heat, aromatic hydrocarbons or other environments which can normally corrode the sealing material. Problems are often encountered in environments containing propane, butane, natural gas, and other chemical materials. Additionally, solenoid valves are often used in high pressure environments which require high seat pressures to obtain a seal. High seat pressures required in high pressure applications often result in cutting or other damage to typical elastomeric seals employed in solenoid valves and other control valves. High pressure environments also result in sticking of the control valve, especially if the seal has been damaged. Contamination of the seal material flowing through the valve also causes leaking and sticking of the valve, especially where flat or tapered seats are utilized. Contamination also causes clogging of small orifices used in pilot operated valves resulting in improper operation. Additionally, more powerful solenoid driving systems which consume more energy and are bulkier and more expensive, are required to overcome inherent friction and produce the seating pressures required for many applications.
Although these problems have been overcome to some extent by ball lock seats such as disclosed in U.S. Pat. No. 904,056, issued Nov. 17, 1908, to Farrell, U.S. Pat. No. 3,217,743, issued Nov. 16, 1965, to Ambille, U.S. Pat. No. 4,008,878, issued Feb. 22, 1977, to Himmelman, U.S. Pat. No. 4,018,419, issued Apr. 19, 1977, to Monpetit, U.S. Pat. No. 4,151,861, issued May 1, 1979, to Bohrdt et al., U.S. Pat. No. 4,057,216, issued Nov. 8, 1977, to Flaschar et al., and U.S. Pat. No. 3,706,323, issued Dec. 19, 1972, to Hayner et al., all of which are specifically incorporated by reference for all that they disclose, the disclosed ball lock seat devices disclosed in the above patents and in the prior art suffer from many disadvantages and limitations. For example, the Himmelman and Farrell references both disclose the use of movable inclined planes to close a ball check valve radially disposed from the direction of motion of the inclined plane. Centering of the ball check valve is accomplished only by way of a tapered seat. Forces generated by the inclined plane are not centered within the tapered seat so that wear is concentrated in a single direction along an area opposite to the inclined plane on the valve seat ridge. Consequently, reliability over extended periods of use is limited due to the uneven surface wear resulting from these ball lock seat devices.